Description: (Taken directly from the application) The objective of this Core Unit is to provide investigators in the field on hematopoietic stem cell biology and gene therapy access to baboons and dogs to test novel concepts before application in humans. The Core Unit will provide three main functions. 1) Provision of a facility for stem cell transplantation in baboons and assistance with the planning and execution of experiments in baboons and dogs. 2) Bone marrow and peripheral blood harvests and CD34 cell selections and transductions. 3) Follow-up of transplanted animals using flow cytometric analysis of hematopoietic subpopulations. To allow monitoring of ex vivo manipulated stem cells after infusion into irradiated animals, cells will be genetically marked. All animals will receive an intravenous catheter that is connected via a tether system to the outside of the cage. This facilitates the daily administration of fluids and broad-spectrum antibiotics and will also be used for reinfusion of transduced baboon CD34 cells. Animals will be examined daily by the Core Unit directors and health status and treatment plan will be discussed with specially trained personnel at the Primate Center. The directors of this Core Unit have extensive experience in conducting stem cell transplantation studies in the baboon. The Primate Center at the University of Washington has set aside a special room for transplantation studies in baboons to accommodate the intensive care required for these studies and the staff at the Primate Center is specially trained to work with baboons involved in stem cell transplantation studies.